CHITOSAN-BASED NANOVACCINE CANDIDATE AGAINST ESCHERICHIA COLI O157:H7

Background and Aim:E. coli O157:H7 is an important entric phathogen in human causing diarrhea, which may be complicated by hemolytic uremic syndrome (HUS). This research aimed at nanovaccination with recombinant protein composed of EspA, Intimin and Tir as important virulence factors expressed by EHEC ( Enterhemorrhagic Escherichia coli).Methods:A chimeric trivalent recombinant protein EIT (EspA,Intimin,Tir) . In present study the rEIT antigen was nanoparticled with chitosan to produce a protective EHEC nanovaccine candidate. Mice were immunized with this antigen and level of immunization IgG and IgA were verified in mice after expression and purification by ELISA. In challenging tests different groups of immunized mice were infected orally with E. coli O157:H7.Results:this nanovaccine candidate induced strong humoral and mucosal immune responses and protected the mice from live challenge with EHEC. After pre incubation of EHEC with antisera the lowest E. coli counts adhering to monolayer Caco-2 cells were in binding inhibition assay. In a challenging study with different groups of immunized mice by feeding EHEC, a reduction in number of colonies was observed in all the immunized groups for over two week.Conclusion:present candidate, reduced signs and symptoms of EHEC infections with efficiency and can be a new strategy for increasing immunity against E. coli O157:H7 and suggests the use of combined (oral –injectable) vaccination routes in orther to achieve a higher humoral and mucosal immunogenicity.

Keywords:

EHEC , Chitosan , Nanovaccine , rEIT